Balloon catheter with porous outer member for air purging

ABSTRACT

A balloon catheter which allows for faster preparation and effective purging of air. The catheter includes an elongated, flexible catheter having a tubular outer member and a tubular inner member each having a respective lumen. The inner member is at least partially disposed in the outer member lumen such that an outer surface of the inner member and an inner surface of the outer member together define an annular inflation lumen. The outer member has micropores or micro-holes configured such that when a contrast agent is injected into the inflation lumen, the micropores or micro-holes allow air to pass therethrough and thereafter become clogged by the contrast agent. The catheter also has a balloon member having its ends secured to and circumferentially around the outer member such that an inner surface of the balloon member and the outer surface of the outer member define an inflatable balloon interior.

RELATED APPLICATION DATA

The present application is a continuation of U.S. patent applicationSer. No. 16/690,981, filed Nov. 21, 2019. The foregoing application ishereby incorporated by reference into the present application in itsentirety.

FIELD OF THE INVENTION

The disclosed inventions generally relate to medical devices and methodsfor performing procedures within a lumen of a vascular system of apatient, and more particularly, to a balloon catheter for use within avascular system, and method of using the same, which is configured toallow for fast and effective purging of unwanted air from ballooncatheter.

BACKGROUND

Various designs of medical catheters have been previously provided forperforming a variety of medical procedures, including interventionaltherapy, drug delivery, diagnosis, perfusion, and the like. In general,medical catheters are used by introducing the catheter through an entrysite of a patient and into the vascular system of the patient, such as avein or artery. The catheter is advanced from the entry site by guidingand pushing the catheter through the vascular system to a target sitefor performing a therapeutic and/or diagnostic medical procedure.

An example of one type of intravascular catheter is a balloon catheterwhich includes an elongated tubular member, wherein a balloon member isaffixed, for example, to a distal end portion of the tubular member orother suitable location to form an inflatable balloon interior betweenan inner surface of the balloon member and the outer surface of thetubular member. One common type of balloon catheter is a balloon guidecatheter which is used to guide other instruments to a desired sitewithin a vascular system. The tubular member includes an inflation lumenextending from a proximal end of the tubular member to the inflatableballoon interior for injecting fluid—to thereby inflate—the balloon.Various types of balloon catheters have been previously disclosed forperforming a variety of different medical procedures. For instance,balloon guide catheters used in conjunction with treating neurologicaldisorders, such as ischemic stroke, are disclosed in U.S. Pat. No.6,638,245 (the '245 patent), the disclosure of which is fullyincorporated herein. FIGS. 13A and 13B illustrate a prior art balloonguide catheter 250 as disclosed in the '245 patent (reference numbershave been changed from the '245 patent). The balloon guide catheter 250comprises an outer tubular member 270 and an inner tubular member 272within the outer tubular member 270. The balloon guide catheter 250 hasan inflatable balloon 260 disposed on the distal end of the outertubular member 270. The annular space between the outer tubular member270 and the inner tubular member 272 forms a fluid supply lumen 258 forinflating the balloon 260. The balloon guide catheter 250 is advanced toa target site within the vascular system of a patient through anintroducer sheath. Once in place, treatment catheters may be advanced tothe target site through the working lumen 252 of the inner tubularmember 272. Accordingly, prior balloon guide catheters, such as theballoon guide catheter 250, required at least three catheter shaftthicknesses (the combined thicknesses of the outer tubular member 270,the inner tubular member 272 and the introducer sheath).

The use of balloon catheters in the neurological vasculature presents anumber of catheter design challenges. For one, the blood vessels in thebrain are typically very small in diameter, as small as severalmillimeters or less, requiring that a catheter advanced into these bloodvessels have an outside diameter as small as one French (0.33 mm).Furthermore, the brain vasculature is highly tortuous, requiring that aneurological catheter be very flexible, especially at the distal end, totravel through and conform to the tortuous path. Also, the blood vesselsof the brain are quite fragile, so a neurological catheter must have asmooth, non-traumatic periphery.

Balloon catheters, including balloon guide catheters, generally requirepreparation prior advancing the balloon catheter into the vasculature ofa patient by purging any unwanted air bubbles out of the respectiveballoon inflation lumen and balloon interior. As described above, aballoon catheter typically has an elongated tube and an inflation lumen.In some cases, a balloon catheter may also have multiple tubes (e.g.,concentric tubes with an inner tube disposed within an outer tube). Eachof these structures, including the tube(s), inflation lumen, and balloonmust be purged of air with a fluid (e.g., saline) prior to advancing theballoon catheter through the vasculature of the patient to prevent airfrom being introduced into the patient which can cause embolisms orother trauma in the patient.

However, due to the closed-end fluid path from the inflation lumen tothe balloon, and in many cases, within the working lumen of the ballooncatheter, it is difficult and very time-consuming to purge all of theair from system. It is also difficult to determine when all of the airhas been purged because of the closed-end fluid paths. As a result,purging the air from prior balloon catheters during preparation forsurgery often takes up to 15 minutes, and even then, the purging is notalways successful. However, due to the closed-end fluid path from theinflation lumen to the balloon, and in many cases, within the tube(s) ofthe catheter, it is difficult and very time-consuming to purge all ofthe air from system. It is also difficult to determine when all of theair has been purged from the catheter because of the closed-end fluidpaths. As a result, purging the air from prior balloon catheters duringpreparation for surgery often takes up to 15 minutes, and even then, thepurging is not always successful.

SUMMARY

The disclosed inventions are directed to balloon catheters having aninnovative configuration which allows for fast preparation and effectivepurging of air within the catheter, including purging air from theballoon inflation lumen and balloon interior. While the description ofthe disclosed inventions will be directed to balloon guide cathetersused for insertion and positioning of therapeutic devices within avascular system of a patient, it is understood that the disclosedinventions are not limited to balloon guide catheters, but may be usedwith any suitable balloon catheter.

As explained above, balloon catheters typically require preparationprior to use, including purging air from the system before advancing thecatheter into the vasculature of a patient. The balloon catheters of thedisclosed inventions are configured to allow fast and effective purgingof air from the catheter, in particular, from the balloon inflationlumen and balloon in a single aspiration step, allowing a simpler andfaster preparation procedure than with existing balloon catheters.

In an exemplary embodiment of the disclosed inventions, a ballooncatheter includes an elongated, flexible, tubular outer member having aproximal portion, a distal portion, and an outer member lumen extendingtherebetween. The outer member is formed of a microporous material suchthat the wall of the outer member has micropores. The micropores areconfigured (e.g., sized) such that the micropores allow air to passthrough the wall of the outer member when a contrast agent is injectedinto the outer member lumen. Air passes from the outer member lumenthrough the micropores to an exterior of the outer member. Typically,the contrast agent is mixed with saline to form a contrast agent/salinemixture, and therefore, the term “contrast agent” as used herein meanscontrast agent, contrast agent/saline mixture, or contrast agent mixedwith any other fluid. Moreover, the micropores allow air to passthrough, and thereafter become clogged by the contrast agent therebysealing the micropores from allowing contrast agent to pass through themicropores.

The balloon catheter further includes a flexible, elongated tubularinner member having a proximal portion, a distal portion, and an innermember lumen extending therebetween. The inner member lumen is incommunication with a distal opening of the inner member. The innermember is at least partially disposed in the outer member lumen suchthat an outer surface of the inner member and an inner surface of theouter member together define an annular inflation lumen.

The balloon member is secured to the outer member. The balloon membercan be secure to any suitable portion of the outer member, including butnot limited to the distal portion. The proximal and distal ends of theballoon are secured to and circumferentially around an outer surface ofthe outer member such that an inner surface of the elastomeric memberand an outer surface of the outer member define an inflatable ballooninterior.

The outer member also has one or more inflation passages through thewall of the outer member that form a fluid pathway between the annularinflation lumen and the balloon interior. The inflation passages may beholes in the through the wall of the outer member which fluidly connectthe annular inflation lumen and the balloon interior.

In various embodiments, the microporous material has micropores having anominal pore size diameter in the range of from 0.1 μm to 2 μm. Thisconfiguration of the microporous material allows air to pass out throughthe micropores of the outer member when contrast agent is injected intothe inflation lumen, and thereafter, the micropores are clogged andsealed by the contrast agent. Further, the pore size diameter of themicropores preferably does not exceed 5 μm, which helps ensure that themicropores can be properly sealed by the contrast agent, withoutallowing excessive contrast agent to leak out through the micropores.

In various embodiments, the microporous material may be any suitablematerial for making a flexible, elongated tube to form the outer member,such as any of the following: TYVEK™ 3345, woven polymer, woven plastic,ePTFE, sintered plastic, sintered polymer, and GORETEX™ fabric membrane.

In various embodiments, the micropores may extend from the proximalportion to the distal portion of the outer member. In this way, thereare micropores for venting air trapped in the inflation lumen along theentire outer member, which decreases the time required to purge air fromthe balloon catheter.

In various embodiments, the microporous material has micropores having anominal pore area size in the range of from 0.079 μm² to 12.5 μm².Similar to the pore size diameter, this feature allows air to pass outthrough the micropores of the outer member when contrast agent isinjected into the inflation lumen, and thereafter, the contrast agentclogs the micropores thereby sealing the micropores from allowingcontrast agent to pass through the micropores.

Another aspect of the disclosed inventions is directed to a method ofpurging air from the above-described exemplary embodiments of theballoon catheter, wherein a contrast agent is injected into the annularinflation lumen and flows through the respective annular inflationlumen, inflation passages, and into the balloon interior, therebypurging air from the inflation lumen and the balloon interior out themicropores of the outer member. A positive pressure of contrast agent ismaintained in the annular inflation lumen such that, after the air ispurged from the inflation lumen and the balloon interior, the contrastagent seals the micropores of the outer member. To complete the purgingof air from the entire balloon catheter, the inner member may be purgedby flushing the inner member lumen with a flushing fluid, such assaline, until the unwanted air is removed from the inner member lumen.The balloon catheter is now prepared (“prepped” for use in a surgicalprocedure). Accordingly, the balloon catheter allows very fast andeffective purging of air in the preparation of the balloon catheter foruse in performing a surgical procedure.

The preparation method may also include positioning the balloon catheterwith the tubular outer member elevated above the balloon such that airtrapped in the balloon is forced into the tubular outer member andpasses out of the tubular member through the micropores of the outermember.

Preferably, contrast agent is injected into the annular inflation lumenwith sufficient pressure to inflate the balloon member. After the air ispurged from the inflation lumen and balloon member, the balloon membermay be deflated by reducing the pressure of contrast agent.

The preparation method may further include inspecting the balloon forair bubbles while the balloon is inflated with contrast agent (e.g., auser visually inspecting the balloon), and determining that any airbubbles in the balloon are purged from balloon. Then, after determiningthat any air bubbles in the balloon are purged from balloon, the balloonis deflated by reducing the pressure of the contrast agent within theinflation lumen and balloon interior.

In one exemplary use, the prepared (air-purged) balloon catheter isinserted into the vascular system of the patient. For example, theballoon catheter may be inserted through an entry incision into an entryblood vessel, such as the inferior vena cava or femoral artery near thegroin. The inner member and outer member are then advanced through thevascular system to position the balloon at a treatment site. The innermember and outer member may be advanced simultaneously, or separately,and at the same rate or different rates. With the balloon positioned atthe treatment site, the balloon member is inflated by injecting contrastagent into the inflation lumen, thereby increasing the pressure ofcontrast agent in the inflation lumen and balloon member. The balloonmay be inflated within the blood vessel such that the balloon seals theblood vessel. This isolates the blood vessel downstream of the balloonfrom the flow of blood. A treatment procedure, such as imaging, embolusremoval, intravascular device implantation, or the like may then beperformed. For example, an imaging catheter may be inserted through theinner member and advanced past the distal end of the inner member toimage the blood vessel or surrounding tissue. In the case of removing anembolus, such as in the treatment of an ischemic stroke, an embolusremoval device may be inserted through the inner member, and advancedpast the distal end of the inner member to grasp or otherwise capturethe embolus, and remove the embolus from the blood vessel.

In an alternate embodiment of the balloon catheter, instead of the outermember being formed of a microporous material, the outer member has animpermeable wall (i.e., impermeable to air, contrast agent and saline)having one or more micro-holes drilled through the wall of the outermember. Thus, in this alternate embodiment, the balloon catheterincludes an elongated, tubular outer member having a proximal portion, adistal portion, and an outer member lumen extending therebetween. Theouter member has one or more micro-holes drilled through the wall of theouter member. The micro-holes are configured such that when a contrastagent is injected into the outer member lumen (i.e., into the inflationlumen), the micro-holes allow air to pass therethrough. In other words,air passes from the outer member lumen (more specifically, the inflationlumen) through the micro-holes to an exterior of the outer member. Inaddition, after allowing air to pass through, the micro-holes becomeclogged by the contrast agent thereby sealing the micro-holes fromallowing contrast agent to pass through the micro-holes.

The alternate embodiment of the balloon catheter also has a flexible,elongated tubular inner member having a proximal portion, a distalportion, and an inner member lumen extending therebetween. The innermember lumen is in communication with a distal opening of the innermember. The inner member is at least partially disposed in the outermember lumen such that an outer surface of the inner member and an innersurface of the outer member together define an annular inflation lumen.

As with the exemplary embodiment, the balloon member is secured to theouter member. The balloon member can be secured to any suitable portionof the outer member, including but not limited to the distal portion.The proximal and distal ends of the balloon are secured to andcircumferentially around an outer surface of the outer member such thatan inner surface of the elastomeric member and an outer surface of theouter member define an inflatable balloon interior. The outer memberalso has one or more inflation passages through the wall of the outermember that form a fluid pathway between the annular inflation lumen andthe balloon interior. The inflation passages may be holes through thewall of the outer member which fluidly connect the annular inflationlumen and the balloon interior.

The micro-holes of this alternate embodiment preferably have a nominalsize diameter in the range of from 5 μm to 8 μm. This configuration ofthe micro-holes allows air to pass out through the micro-holes of theouter member when contrast agent is injected into the inflation lumen,and thereafter, the contrast agent clogs the micro-holes thereby sealingthe micro-holes. In another aspect, the density of the micro-holes overthe surface area of the outer member preferably does not exceed 16micro-holes per cm² of surface area of the outer member. Alternatively,the density of the micro-holes over the surface area of the outer memberpreferably does not exceed 20 micro-holes per cm² of surface area of theouter member, or 10 micro-holes per cm² of surface area of the outermember, or 5 micro-holes per cm² of surface area of the outer member.This maximum density of the micro-holes over the surface area of theouter member helps ensure that the contrast agent will seal themicro-holes without allowing contrast agent (or an excessive amount ofcontrast agent) to leak out through the micro-holes.

As with the exemplary embodiment, the outer member of the alternateembodiment is preferably formed from a material, such as polyurethane,PEBAX™, VESTAMID™, a thermoplastic elastomer, and nylon, or othersuitable material from which a flexible, elongated, tubular outer membermay be formed, and micro-holes may be drilled through a wall of thetubular outer member. The micro-holes may be drilled using any suitablemeans, such as laser drilling, mechanical drilling, punching, etc., andare preferably positioned spaced apart along the outer member from theproximal portion to the distal portion of the outer member. Forinstance, the micro-holes can be arranged in a helical pattern along theouter member, or in a rectangular matrix, or other suitable pattern. Themicro-holes preferably have a nominal hole area in the range of from 1μm² to 210 μm². Similar to the nominal diameter, the nominal hole areaallows air to pass out through the micro-holes of the outer member whencontrast agent is injected into the inflation lumen, and the contrastagent clogs and seals the micro-holes after the air has been vented.

Another aspect of the disclosed inventions is directed to a method ofpurging air from the alternate embodiment of a balloon catheter. Thisair purging method is essentially the same as the method of purging airfrom the exemplary embodiment, except that air is purged out through themicro-holes, and the contrast agent seals the micro-holes, instead ofthe micropores.

Accordingly, embodiments described herein provide an innovative balloonand methods of using the same which allow for faster preparation andmore effective purging of air within the catheter than prior ballooncatheters.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing, along with other and further embodiments and aspects ofthe disclosed inventions, with now be described in greater detail in thebelow detailed description, to be read in view of the accompanyingfigures, wherein like reference numerals refer to like elements and thedescription for like elements shall be applicable for all describedembodiments wherever relevant.

FIG. 1 is a side view of a balloon guide catheter in accordance with afirst embodiment of the disclosed inventions;

FIG. 2 is a side, cross-sectional view of the balloon guide catheter ofFIG. 1;

FIG. 3 depicts the balloon guide catheter of FIG. 1 being purged of airby injecting a contrast agent into the inflation lumen and air passingthrough the micropores of the outer member;

FIG. 4 depicts the balloon guide catheter of FIG. 1 being purged of airwith the balloon member inflated, and air passing through the microporesof the outer member;

FIG. 5 depicts balloon guide catheter of FIG. 1 after the micropores areclogged and sealed by contrast agent and the balloon member has beendeflated;

FIG. 6 depicts the balloon guide catheter of FIG. 1 with the innermember lumen being purged of air by injecting saline into the innermember lumen;

FIG. 7 is a side view of a balloon guide catheter in accordance with asecond embodiment of the disclosed inventions;

FIG. 8 is a side, cross-sectional view of the balloon guide catheter ofFIG. 7;

FIG. 9 depicts the balloon guide catheter of FIG. 7 being purged of airby injecting a contrast agent into the inflation lumen and air passingthrough the micro-holes of the outer member;

FIG. 10 depicts the balloon guide catheter of FIG. 7 being purged of airwith the balloon member inflated, and air passing through themicro-holes of the outer member;

FIG. 11 depicts balloon guide catheter of FIG. 7 after the micro-holesare clogged and sealed by contrast agent and the balloon member has beendeflated;

FIG. 12 depicts the balloon guide catheter of FIG. 7 with the innermember lumen being purged of air by injecting saline into the innermember lumen;

FIGS. 13A and 13B depict a prior art balloon guide catheter, asdisclosed in the U.S. Pat. No. 6,638,245.

DETAILED DESCRIPTION

FIGS. 1-5 illustrate a first embodiment of a balloon guide catheter 100constructed in accordance with a first one embodiment of the disclosedinventions. The balloon guide catheter 100 is configured generally forperforming a procedure within a vascular system, such as treatingischemic strokes and/or for blocking or restricting blood flow for othertreatment or diagnostic purposes. In particular with respect to thedisclosed inventions, the balloon guide catheter 100 is speciallyconfigured to allow for fast preparation of the catheter for performinga surgical procedure, including providing for fast and effective purgingof air from the respective inflation lumen 121 and balloon interior 146,as described in greater detail below.

The balloon guide catheter 100 includes an elongated, flexible, tubularbody 102 having a proximal portion 104, a distal portion 106 and aninner working lumen 108 extending therebetween. The working lumen 108(defined in part by a hub 116 and in part by an inner member lumen 140)is in fluid communication with a distal opening 110 at a distal end 112of the tubular body 102, and with a proximal opening 114 defined by ahub 116 (further described below) secured to the proximal portion 104 ofthe tubular body 102.

The tubular body 102 includes an elongated, flexible, tubular outermember 118 having a proximal portion 124 and a distal portion 126, andan outer member lumen 128 extending therebetween. The tubular body 102also has an elongated, flexible, tubular inner member 120 coaxiallydisposed within the outer member lumen 128, such that the outer surfaceof the inner member 120 and the inner surface of the outer member 118together define an annular inflation lumen 121.

The outer member 118 is formed of a microporous material such that thewall of the outer member 118 has micropores 122 along the entire wall ofthe outer member 118 extending from the proximal portion 124 to thedistal portion 126. The micropores 122 are shown schematically in thefigures, as the micropores 122 are quite small, and are distributed overthe entire wall of the outer member 118. The microporous material hasmicropores 122 configured to allow air to pass through the wall of theouter member 118 when a contrast agent 123 is injected into the outermember lumen 128 (more specifically, into the inflation lumen 121) fromthe inflation lumen 121 out to the exterior of the outer member 118, asdepicted by the arrows 132 in FIGS. 3 and 4. The configuration of themicropores 122 of the microporous material also provide for themicropores 122 to be clogged by the contrast agent 123 after the air ispurged from the inflation lumen 121 and balloon member 134. In order toboth purge the unwanted air and provide the contrast agent cloggingeffect, the microporous material has micropores 122 having a nominalpore size diameter ranging from 0.1 μm to 2.0 μm. In another way ofdefining the size of the microporous material, the micropores 122 have anominal pore area size ranging from 0.079 μm² to 12.5 μm². In addition,the pore size diameter of the micropores 122 should not exceed 5 μm, inorder to ensure that the micropores are properly clogged by the contrastagent after the air is purged. Thus, the microporous material may be anysuitable material having properly configured micropores 122, includingwithout limitation, TYVEK™ 3345, woven polymer, woven plastic, ePTFE,sintered plastic, sintered polymer, and GORETEX™ fabric membrane.

The inner member 120 has a proximal portion 136, a distal portion 138,and an inner member lumen 140 extending therebetween. The inner member120 may each be made of a polymeric tube, or other suitable material,and may have one or more reinforcing members (not shown) to providereinforced and/or stiffened portions. For example, a coil, braid,ribbon, hypotube, or other structural member may be disposed on theinside, on the outside, and/or embedded within a wall of the innermember 120. Such reinforcing members may be made of any suitablematerial, such as a super-elastic alloy or shape-memory material toprovide a specific shape to the reinforced portion of the tubular body102 under certain conditions.

As mentioned above, the balloon guide catheter 100 further includes ahub 116 secured to the proximal portion 104 of the tubular body 102(i.e., to each of the inner and outer members 118 and 120). The hub 116defines the proximal end opening 114 of the working lumen 108. The hub116 includes a balloon inflation port 142 in fluid communication withthe proximal end of the inflation lumen 121. The balloon inflation port142 is configured to be connected to an inflation syringe 152 (not drawnto scale) (see FIGS. 3-5) or other source of pressurized inflation fluidfor purging air from the balloon guide catheter 100 when prepping thecatheter 100 for a surgical procedure. For example, the ballooninflation port 142 may have a female Luer lock (not shown) for attachingthe inflation syringe 152 or other fluid source, having a mating maleLuer lock (not shown).

The inflation lumen 121 extends along the length of the outer member 118from the balloon inflation port 142 to an inflatable balloon interior146 (best seen in FIG. 5 in which the balloon interior 146 is deflated)of a balloon member 134 secured to the outer member 118. In theillustrated first embodiment, the outer member 118 and inner member 120are connected at the distal portion 126 of the outer member 118 therebyforming the distal end of the inflation lumen 121. The outer member 118and inner member 120 may also be bonded to each other at one or moreother locations (not shown) distal of the hub 116. However, such bondsare not fully circumferential so as to ensure the inflation lumen 121 iscontinuous from the inflation port 142 to the balloon interior 36.Alternative to the annular inflation lumen 121, the inflation lumen 121may be one or more channels, conduits, tubes, etc., formed in the wallof the outer member 118. Alternatively, the inflation lumen 121 may beone or more channels, conduits, tubes, etc., formed in, or attached to,the wall of the outer member 118.

The hub 116 also has a working lumen port 143 which is in fluidcommunication with the working lumen 108. The working lumen port 143 isconfigured to be connected to a source of purging fluid (e.g., saline)to purge air from the working lumen 108. A source of flushing fluid(e.g., saline) and/or a source of fluid medication may be connected tothe working lumen port 143 during a surgical procedure with the balloonguide catheter 100 in order to flush the target a target site within avascular system, and/or to deliver medication to the target site. Theworking lumen port 143 may have a female Luer lock (not shown) forattaching a syringe 68 or other fluid source having a mating male Luerlock, such as a syringe 155 (see FIG. 5).

In the illustrated embodiment, the balloon member 134 is secured to thedistal portion 126 of the outer member 118. However, the balloon member134 may be secured to any suitable location on the outer member 118,including proximal to the distal portion 126, or in the middle portionof the outer member 118, etc. The balloon member 134 is typicallyelastomeric, but may also be non-elastomeric. The balloon member 134 maybe transparent, or translucent (i.e., semitransparent), so that theballoon member 134 can be visually inspected for air bubbles whilepurging air from the catheter 100, as described herein. The proximal end148 and distal end 150 of the balloon member 134 are secured to, andcircumferentially around, the outer surface of the outer member 118. Inthis way, the inner surface of the balloon member 134 and the outersurface of the outer member 118 form the inflatable balloon interior146. The outer member 118 and inner member 120 may be bonded to eachother at one or more locations (not shown) distal of the hub 19.However, such bonds are not fully circumferential so as to ensure theinflation lumen 121 is continuous from the inflation port 142 to theballoon interior 146.

The outer member 118 has one or more balloon inflation passages 156through the wall of the outer member 118 within the balloon interior.The inflation passages 156 form a fluid pathway through the wall of theouter member between the inflation lumen 121 and the inflatable ballooninterior 146. In the illustrated embodiment, the outer member 118 has 4inflation passages 156, wherein the inflation passages 156 are spacedlongitudinally along the outer member 118, and circumferentially aroundthe outer member 118 (in the illustrated embodiment, the inflationpassages are spaced 180° around the circumference of the outer member118). The balloon guide catheter 100 may have any suitable number ofinflation passages 156, such as between 1 and 10 inflation passages 156.

A method of purging air from the balloon guide catheter 100 in order toprepare (“prep”) the catheter 100 for use in a medical procedure, willnow be described with reference to FIGS. 1-6. As shown in FIG. 2, theballoon guide catheter 100 is first provided without any liquid in thecatheter 100, such that there is air in the inflation lumen 121 and theworking lumen 108. In order to prep the balloon guide catheter 100 to beused in a surgical procedure, the air is purged from the catheter 100,including the inflation lumen 121 and the working lumen 108. The methodwill described with purging the inflation lumen 121 first, and theworking lumen 108 thereafter, but the method can also be performed inthe reverse order, or even purging both simultaneously.

Referring to FIG. 2, in order to purge air from the inflation lumen 121,a source 152 of contrast agent 123 is attached to the inflation port142. In the illustrated embodiment, the source of contrast agent 123 isthe inflation syringe 152 filled with contrast agent 123. The syringe152 may have a male Luer lock which mates with the female Luer lock ofthe inflation port 142. The syringe 152 is used to inject the contrastagent 123 into the inflation port 142, into the inflation lumen 121 andinto the balloon member 134. As the inflation lumen 121 is filled withcontrast agent 123, the air in the inflation port 142, inflation lumen121 and the balloon member 134 is forced out through the micropores 122to the exterior of the outer member 118 as indicated by the arrows 132.The syringe 152 is used to maintain a positive pressure of contrastagent 123 in the inflation port 142, inflation lumen 121 and balloonmember 134.

As shown in FIG. 4, after the inflation port 142, inflation lumen 121and balloon member 134 are filled with contrast agent 123, additionalcontrast agent 123 is injected into the inflation port 142 using thesyringe 152 which inflates the balloon member 134. Air continues to bepurged out of through the micropores 122. The balloon guide catheter 100is then manipulated to position the outer member 118 above the balloonmember 134 (in other words, positioning the balloon member 134 below theremainder of the balloon guide catheter 100 proximal to the balloonmember 134) so that any air remaining in the balloon member 134 isforced into the outer member 118 and then passes out through themicropores 122 of the outer member 118. The positioning of the balloon134 below the outer member 118 may be also be done at any other timeduring the purging of air from the inflation lumen 121 and balloonmember 134, such as before initially injecting contrast agent into theinflation port 142, inflation lumen 121 and balloon 134, or just priorto inflating the balloon member 134, etc.

With the balloon member 134 inflated, the balloon member 134 is visuallyinspected for air (e.g., inspecting for air bubbles), by a user preppingthe balloon guide catheter 100. The user determines whether any air isremaining in the balloon member 134. The balloon member 134 may also bevisually inspected for any leaks. If the balloon member 134 has leaks,the balloon guide catheter 100 may be rejected and replaced. If theballoon member 134 is confirmed to have no leaks, then the method ofprepping the balloon guide catheter 100 may proceed.

As the air is being forced out through the micropores 122 of the outermember 118, the contrast agent 123 clogs the micropores 122. As shown inFIG. 5, the clogged micropores 158 are depicted by the lines 158. Theclogged micropores 158 are sealed by the contrast agent 123 fromallowing contrast agent 123 to pass through the micropores 122. Asdescribed herein, the micropores 122 are configured to allow air to bepurged out through micropores 122 from the inflation lumen 121, andthereafter, are clogged and sealed by the contrast agent 123. Also, asshown in FIG. 5, after the air is purged from the inflation lumen 121and balloon member 134, the balloon member 134 is deflated so that itcan be inserted into a vascular system uninflated. The air is now purgedfrom the inflation port 142, inflation lumen 121 and balloon member 134,and the balloon member 134 is deflated.

As depicted in FIG. 6, prepping the balloon guide catheter 100 may alsoinclude purging air from working lumen 108, including inner member lumen140 of the inner member 120 and the working lumen port 143. A source offlushing fluid, typically a purging syringe 155 filled with saline 160,is connected to the working lumen port 143. The syringe 155 may have amale Luer lock which mates with the female Luer lock of the workinglumen port 143. The syringe 155 is used to inject the saline 160 intothe working lumen 108 thereby purging air from the working lumen 108,including the inner member lumen 140 of the inner member 120 and theinflation port 142. The user may visually inspect the saline 160 exitingthe distal opening 110 of the inner member lumen 140 for air bubbles,and when there are no air bubbles, the working lumen 108 is purged ofair. The working lumen 108 remains filled with saline 160 in the preppedballoon guide catheter 100 (e.g., surface tension retains the saline 160within the working lumen 108).

The balloon guide catheter 100 is now purged of air, and fully preppedfor use in a surgical procedure.

The method of using the prepped balloon guide catheter 100 in a medicalprocedure may include any suitable use of the balloon guide catheter100. In one exemplary method, the balloon guide catheter 100 is insertedinto the vascular system of the patient. For example, the balloon guidecatheter 100 may be inserted through an entry incision into an entryblood vessel, such as the inferior vena cava or femoral artery near thegroin. The balloon guide catheter 100, including the inner member 120,outer member 118, and balloon member 134, are advanced through thevascular system to position the balloon 134 at a treatment site. Thecontrast agent 123 allows the user to track the position of the balloonguide catheter 100 using a suitable medical imaging device, such as aradiography machine, MM, etc. The inner member 120 and outer member 118may be advanced simultaneously, or separately, and at the same rate ordifferent rates. In the illustrated embodiment, the inner member 120 andouter member 118 are connected at the distal portion 126 of the outermember 118 so they are advanced simultaneously.

With the balloon member 134 positioned at the treatment site, theballoon member 134 is inflated by injecting contrast agent into theinflation lumen 121 using the inflation syringe 152 (or other suitablesource of inflation fluid), thereby increasing the pressure of contrastagent 123 in the inflation lumen 121 and balloon member 134. The balloonmember 134 may be inflated within the blood vessel such that the balloonmember 134 seals the blood vessel. This isolates the blood vesseldownstream of the balloon member 134 from the flow of blood. The syringe152 may also be used to inject saline 160 to the treatment site, toflush the treatment site. A syringe 152 of medication or othertherapeutic substance may be used to inject the medication or othersubstance to the treatment site. Alternatively, or in addition, atreatment procedure, such as imaging, embolus removal, intravasculardevice implantation, or the like may be performed. For example, animaging catheter may be inserted through the working lumen 108,including the inner member lumen 140, and advanced past the distal endof the inner member 120 to image the blood vessel or surrounding tissue.In the case of removing an embolus, such as in the treatment of anischemic stroke, an embolus removal device may be inserted through theinner member lumen 140, and advanced past the distal end 112 of theinner member 118 to grasp or otherwise capture the embolus, and removethe embolus from the blood vessel.

Turning to FIGS. 7-12, a second embodiment of a balloon guide catheter200 is illustrated. The balloon guide catheter 200 is also speciallyconfigured to allow for fast preparation of the catheter for performinga surgical procedure, including providing for fast and effective purgingof air from the respective inflation lumen 121 and balloon interior 146,as described herein. The balloon guide catheter 200 is substantially thesame as the balloon guide catheter 100, except that instead of the outermember 118 being formed of a microporous material, the outer member hasan impermeable wall having one or more micro-holes 202 drilled throughthe wall of the outer member 118.

Accordingly, the outer member 118 has one or more micro-holes 202drilled through the wall of the outer member 118. The micro-holes 202are configured such that when the contrast agent 123 is injected intothe inflation lumen 121 using the syringe 152, the micro-holes 202 allowair to pass therethrough to the exterior of the outer member 118. Inother words, air passes from the outer member lumen (more specifically,the inflation lumen) through the micro-holes to an exterior of the outermember. In addition, after allowing air to pass through, the micro-holesbecome clogged by the contrast agent thereby sealing the micro-holesfrom allowing contrast agent to pass through the micro-holes.

The outer member 118 may be formed from any suitable material, such aspolyurethane, PEBAX™, VESTAMID™, a thermoplastic elastomer, and nylon,or other suitable material from which a flexible, elongated, tubularouter member may be formed, and micro-holes may be drilled through awall of the tubular outer member. The micro-holes 202 may be drilledusing any suitable means, such as laser drilling, mechanical drilling,punching, etc.

In order to both purge the unwanted air and provide the contrast agentclogging effect, the micro-holes 202 have a nominal size diameter in therange of from 5 μm to 8 μm. This configuration of the micro-holes 202allows air to pass out through the micro-holes 202 of the outer member118 when contrast agent 123 is injected into the inflation lumen 121,and thereafter, the contrast agent 123 clogs the micro-holes 202 therebysealing the micro-holes from allowing contrast agent 123 to leak out.Alternatively, or in addition, the size of the micro-holes 202 may bedefined in term of area. For instance, the micro-holes 202 have anominal hole area in the range of from 1 μm² to 210 μm². Similar to thenominal diameter, the nominal hole area allows air to pass out throughthe micro-holes 202 of the outer member 118 when contrast agent isinjected into the inflation lumen 121, and the contrast agent 123 clogsand seals the micro-holes 202 after the air has been purged.

The density of the micro-holes 202 over the surface area of the outermember 118 may have a maximum density in order to ensure that thecontrast agent 123 will seal the micro-holes 202 without allowingcontrast agent 118 (or an excessive amount of contrast agent) to leakout through the micro-holes 202. The density of the micro-holes 202 overthe surface area of the outer member 118 preferably does not exceed 16micro-holes per cm² of surface area of the outer member 118.Alternatively, the density of the micro-holes 202 over the surface areaof the outer member 118 does not exceed 20 micro-holes per cm² ofsurface area of the outer member 118, or 10 micro-holes per cm² ofsurface area of the outer member 118, or 5 micro-holes 202 per cm² ofsurface area of the outer member 118.

The micro-holes 202 are spaced apart along the outer member 118 from theproximal portion 124 to the distal portion 126 of the outer member 118.The micro-holes 202 may be arranged in a pattern along the outer member118, such as one or more helical patterns along the outer member 118, orin a rectangular matrix, or other suitable pattern.

As shown in FIGS. 7-12, the method of prepping balloon guide catheter200 for use in a surgical procedure is substantially the same as themethod of prepping the balloon guide catheter 100. As shown in FIG. 8,the balloon guide catheter 200 is first provided without any liquid inthe catheter 200, such that there is air in the inflation lumen 121 andthe working lumen 108. In order to prep the balloon guide catheter 200to be used in a surgical procedure, the air needs to be purged from thecatheter 200, including the inflation lumen 121 and the working lumen108. Same as the catheter 100, the method will described with purgingthe inflation lumen 121 first, and the working lumen 108 thereafter, butthe method can also be performed in the reverse order, or even purgingboth simultaneously.

Turning to FIG. 9, in order to purge air from the inflation lumen 121, asource 152 of contrast agent 123 is attached to the inflation port 142.Again, the source of contrast agent 123 is the inflation syringe 152filled with contrast agent 123. The syringe 152 may have a male Luerlock which mates with the female Luer lock of the inflation port 142.The syringe 152 is used to inject the contrast agent 123 into theinflation port 142, into the inflation lumen 121 and into the balloonmember 134. As the inflation lumen 121 is filled with contrast agent123, the air in the inflation port 142, inflation lumen 121 and theballoon member 134 is forced out through the micro-holes 202 to theexterior of the outer member 118 as indicated by the arrows 132. Thesyringe 152 is used to maintain a positive pressure of contrast agent123 in the inflation port 142, inflation lumen 121 and balloon member134.

As shown in FIG. 10, after the inflation port 142, inflation lumen 121and balloon member 134 are filled with contrast agent 123, additionalcontrast agent 123 is injected into the inflation port 142 using thesyringe 152 which inflates the balloon member 134. Air continues to bepurged out of through the micro-holes 202. The balloon guide catheter200 is then manipulated to position the outer member 118 above theballoon member 134 (in other words, positioning the balloon member 134below the remainder of the balloon guide catheter 200 proximal to theballoon member 134) so that any air remaining in the balloon member 134is forced into the outer member 118 and then passes out through themicro-holes 202 of the outer member 118. The positioning of the balloon134 below the outer member 118 may be also be done at any other timeduring the purging of air from the inflation lumen 121 and balloonmember 134, such as before initially injecting contrast agent into theinflation port 142, inflation lumen 121 and balloon 134, or just priorto inflating the balloon member 134, etc.

With the balloon member 134 inflated, the balloon member 134 is visuallyinspected for air (e.g., inspecting for air bubbles), by a user preppingthe balloon guide catheter 200. The user determines whether any air isremaining in the balloon member 134. The balloon member 134 may also bevisually inspected for any leaks. If the balloon member 134 has leaks,the balloon guide catheter 200 may be rejected and replaced. If theballoon member 134 is confirmed to have no leaks, then the method ofprepping the balloon guide catheter 200 may proceed.

As the air is being forced out through the micro-holes 202 of the outermember 118, the contrast agent 123 clogs the micro-holes 202. As shownin FIG. 11, the micro-holes 202 are sealed by the plugs 204 formed bythe contrast agent 123. The clogged micro-holes 202 are sealed by thecontrast agent 123 from allowing contrast agent 123 to pass through themicro-holes 202. As described herein, the micro-holes 202 are configuredto allow air to be purged out through micro-holes 202 from the inflationlumen 121, and thereafter, are clogged and sealed by the contrast agent123. Also, as shown in FIG. 11, after the air is purged from theinflation lumen 121 and balloon member 134, the balloon member 134 isdeflated so that it can be inserted into a vascular system uninflated.The air is now purged from the inflation port 142, inflation lumen 121and balloon member 134, and the balloon member 134 is deflated.

Prepping the balloon guide catheter 200 may also include purging airfrom the working lumen 108, including inner member lumen 140 of theinner member 120 and the working lumen port 143. The purging syringe 155filled with saline 160 is connected to the working lumen port 143. Thesyringe 155 may have a male Luer lock which mates with the female Luerlock of the working lumen port 143. The syringe 155 is used to injectthe saline 160 into the working lumen 108 thereby purging air from theworking lumen 108, including the inner member lumen 140 of the innermember 120 and the inflation port 142. The user may visually inspect thesaline 160 exiting the distal opening 110 of the inner member lumen 140for air bubbles, and when there are no air bubbles, the working lumen108 is purged of air. The working lumen 108 remains filled with saline160 in the prepped balloon guide catheter 200 (e.g., surface tensionretains the saline 160 within the working lumen 108).

The balloon guide catheter 200 is now purged of air, and fully preppedfor use in a surgical procedure.

The method of using the prepped balloon guide catheter 200 in a medicalprocedure is substantially the same as for prepped balloon guidecatheter 100, as described herein.

Although particular embodiments have been shown and described, it is tobe understood that the above description is not intended to limit thescope of these embodiments. While embodiments and variations of the manyaspects of the invention have been disclosed and described herein, suchdisclosure is provided for purposes of explanation and illustrationonly. Thus, various changes and modifications may be made withoutdeparting from the scope of the claims. For example, not all of thecomponents described in the embodiments are necessary, and the inventionmay include any suitable combinations of the described components, andthe general shapes and relative sizes of the components of the inventionmay be modified. Accordingly, embodiments are intended to exemplifyalternatives, modifications, and equivalents that may fall within thescope of the claims. The invention, therefore, should not be limited,except to the following claims, and their equivalents.

What is claimed is:
 1. A balloon catheter, comprising: an elongated, tubular outer member having a proximal portion, a distal portion, and an outer member lumen extending therebetween, the tubular outer member having one or more micro-holes through a wall of the outer member, the one or more micro-holes configured such that when a contrast agent is injected into the outer member lumen, the micro-holes allow air to pass therethrough and thereafter become clogged by the contrast agent and thereby seal the one or more micro-holes from allowing contrast agent to pass through the micro-holes; a balloon member secured to an outer surface of the outer member, and having an inflatable balloon interior; and an inflation lumen in fluid communication with the inflatable balloon interior and the outer member lumen.
 2. The balloon catheter of claim 1, wherein the outer member is formed of a microporous material, the micro-holes are micropores of the microporous material and the micropores have a nominal pore size diameter in a range of from 0.1 μm to 2 μm.
 3. The balloon catheter of claim 2, wherein the pore size diameter of the micropores does not exceed 5 μm.
 4. The balloon catheter of claim 2, wherein the microporous material is selected from the group consisting of woven polymer, woven plastic, ePTFE, sintered plastic, and sintered polymer.
 5. The balloon catheter of claim 2, wherein the micropores extend from the proximal portion to the distal portion of the outer member.
 6. The balloon catheter of claim 2, wherein the microporous material has micropores having a nominal pore area size in a range of from 0.079 μm² to 12.5 μm².
 7. The balloon catheter of claim 1, wherein the micro-holes are micro-holes drilled through a wall of the outer member and the micro-holes have a nominal size diameter in a range of from 5 μm to 8 μm.
 8. The balloon catheter of claim 7, wherein the outer member is formed from a material selected from the group consisting of polyurethane, a thermoplastic elastomer, and nylon.
 9. The balloon catheter of claim 7, wherein the micro-holes extend from the proximal portion to the distal portion of the outer member.
 10. The balloon catheter of claim 7, wherein the micro-holes have a nominal hole area in a range of from 1 μm² to 210 μm².
 11. The balloon catheter of claim 1, wherein the balloon member has respective proximal and distal ends secured to and circumferentially around an outer surface of the distal portion of the outer member such that an inner surface of the balloon member and the outer surface of the outer member together define the inflatable balloon interior.
 12. The balloon catheter of claim 1, further comprising: a tubular inner member having a proximal portion, a distal portion, and an inner member lumen extending therebetween, wherein the inner member lumen is in communication with a distal opening of the inner member, the inner member being at least partially disposed in the outer member lumen such that an outer surface of the inner member and an inner surface of the outer member together define an annular space which forms the inflation lumen; and wherein, the outer member has one or more inflation passages through the wall of the outer member that form a fluid pathway between the inflation lumen and the balloon interior.
 13. The balloon catheter of claim 12, wherein the balloon member has respective proximal and distal ends secured to and circumferentially around an outer surface of the distal portion of the outer member such that an inner surface of the balloon member and the outer surface of the outer member together define the inflatable balloon interior.
 14. A method of purging air from the balloon catheter of claim 1, comprising: injecting a contrast agent into the inflation lumen, through the outer member and into the balloon member thereby purging air from the inflation lumen, the balloon interior, and the outer member out through the micro-holes of the outer member; and maintaining a positive pressure of contrast agent in the inflation lumen such that the contrast agent seals the micro-holes of the outer member.
 15. The method of claim 14, wherein the contrast agent is injected into the inflation lumen with sufficient pressure to inflate the balloon member, and wherein the method further comprises: positioning the balloon catheter with the tubular outer member elevated above the balloon member such that air trapped in the balloon member is forced into the tubular outer member and passes out of the outer member through the micro-holes of the outer member.
 16. The method of claim 14, further comprising: inspecting the balloon member for air bubbles while the balloon member is inflated with contrast agent; determining that any air bubbles in the balloon member are purged from balloon; and after determining that any air bubbles in the balloon member are purged from balloon member, deflating the balloon member by reducing the pressure of the contrast agent within the inflation lumen and balloon interior. 